They are formed when the water in jet exhaust mixes with wet cold air, and condenses and freezes into ice crystals.
Which animal is the tallest in the world?
Giraffes are the tallest animals in the world. Males can grow up to 5.5 meters tall, females can reach 4.3 meters tall and their babies, called calves, are born 1.8 meters tall.
How many types of bones are there?
There are five types of bones in the human body: long, short, flat, irregular, and sesamoid.
Can dogs see in color or just black and white?
Veterinarians used to believe that dogs saw only in black and white, but recent studies suggest that they actually do have some color vision—but it’s not as bright as a human’s.